The Ruthenian territories and states include:
The name Ruthenia is latinized form of Rus. Until modern times it was applied to territories inhabited by speakers of East Slavic languages (Russian, Ukrainian, Belorusian) or to territories of contemporary Ukraine only.
There are many theories connected to the origins of the name of Rus. In the 10th century all Eastern Slavic tribes were known as Ruthenians (Rusy). It was believed that the first attempt to consolidate Eastern Slavic tribes was made by the Viking named Rurik. But today it is generally accepted to see the direct connection not to the Viking but to the prince of Baltic Slavs known in history by the same name.
Further reading: Kievan Rus'
After the feudal fragmentation of Ruthenia into several duchies, most of them were subjugated by the Grand Duchy of Lithuania, later in personal union with the Kingdom of Poland to form the Polish-Lithuanian Commonwealth (The Commonwealth of the Two Nations). There were serious attempts to change this union into the Commonwealth of the Three Nations: Poland, Lithuania (including Belarus) and Ruthenia Ukraine (the Duchy of Ruthenia).
The fragmentation of Kievan Rus' and its subjugation to external empires was the basis for the split of Ruthenians into three separate nations. Ruthenians subjugated by the Mongol Empire would become Russians and those incorporated to Lithuania would become Ukrainians and Belarusians.
3. Ruthenia or Carpato-Ruthenia or Carpatho-Ukraine is the name of a region in Central Europe comprising the southern slopes of the Carpathian Mountains. It is now part of Ukraine. It takes its name from the Ruthenes (also called Rusyns, Rusins, Carpatho-Rusin, Russniaks), a small Slavonic people related to the Ukrainians and Slovaks.
Before World War I Ruthenia was part of Hungary. It became part of Czechoslovakia after the Treaty of Trianon in 1920. Following Adolf Hitler's seizure of the country in 1939, Ruthenia briefly proclaimed its independence, before being annexed by Hungary. After World War II it was ceded to the Soviet Union and included into the Ukrainian Soviet Socialist Republic; the latter is independent Ukraine since 1991.